Here are two replies to your question:
Add 1 teaspoon baking powder.
Add 1 egg white
I think you may need up to 6 cups of flour, as our flours seem to need less water often, but I'd start with the 5. I'd use my standard mix and definately NOT use one that had lots of flours with flavor (like bean or sorghum)...
I'd add up to 2 TBLS (6 teaspoons...